U.S. patent application number 13/401927 was filed with the patent office on 2013-08-22 for solenoid-actuated pressure control valve.
This patent application is currently assigned to DELPHI TECHNOLOGIES, INC.. The applicant listed for this patent is FRANCISCO MORALES, ALEJANDRO MORENO. Invention is credited to FRANCISCO MORALES, ALEJANDRO MORENO.
Application Number | 20130214187 13/401927 |
Document ID | / |
Family ID | 47722149 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130214187 |
Kind Code |
A1 |
MORENO; ALEJANDRO ; et
al. |
August 22, 2013 |
SOLENOID-ACTUATED PRESSURE CONTROL VALVE
Abstract
A valve assembly includes a hydraulic subassembly with a valve
member displaceable along a valve axis for controlling flow of
fluid. The valve assembly also includes a solenoid subassembly for
selectively displacing said valve member. The solenoid subassembly
includes a metallic solenoid housing having an open end and a
solenoid housing base. The solenoid subassembly also includes a
solenoid coil assembly disposed within the solenoid housing, the
solenoid coil assembly having a coil wound around a plastic spool
defining a spool bore extending through the spool. The solenoid
subassembly also includes a metallic solenoid housing cover closing
off the open end of the solenoid housing and attached to the
solenoid housing with a crimp connection. The solenoid subassembly
also includes a metallic column disposed within and passing through
the spool bore extending from the solenoid housing base to the
solenoid housing cover.
Inventors: |
MORENO; ALEJANDRO; (EL PASO,
TX) ; MORALES; FRANCISCO; (CD. JUAREZ, MX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
MORENO; ALEJANDRO
MORALES; FRANCISCO |
EL PASO
CD. JUAREZ |
TX |
US
MX |
|
|
Assignee: |
DELPHI TECHNOLOGIES, INC.
Troy
MI
|
Family ID: |
47722149 |
Appl. No.: |
13/401927 |
Filed: |
February 22, 2012 |
Current U.S.
Class: |
251/129.15 |
Current CPC
Class: |
F16K 31/0675 20130101;
F16K 31/0665 20130101; F16K 27/029 20130101; F16K 31/0655 20130101;
H01F 2007/085 20130101 |
Class at
Publication: |
251/129.15 |
International
Class: |
F16K 31/02 20060101
F16K031/02 |
Claims
1. A valve assembly having a hydraulic subassembly with a valve
member displaceable along a valve axis for controlling at least one
of flow and pressure of fluid from a fluid source to a working
device, said valve assembly also having a solenoid subassembly for
selectively displacing said valve member, said solenoid subassembly
comprising: a metallic solenoid housing having an open end distal
from said hydraulic subassembly and a solenoid housing base
adjacent to and connected with said hydraulic subassembly; a
solenoid coil assembly disposed within said solenoid housing, said
solenoid coil assembly having a coil wound around a plastic spool
defining a spool bore extending through said spool; a metallic
solenoid housing cover closing off said open end of said solenoid
housing and attached to said solenoid housing with a crimp
connection that creates a compressive crimp force acting along said
valve axis; and a metallic column disposed within and passing
through said spool bore, said metallic column extending from said
solenoid housing base to said solenoid housing cover; wherein said
compressive crimp force is transferred through said metallic column
from said solenoid housing base to said solenoid housing cover to
isolate said compressive crimp force from plastic components.
2. A valve assembly as in claim 1 wherein said metallic column
comprises: a primary pole piece of said solenoid subassembly; and a
secondary pole piece of said solenoid subassembly.
3. A valve assembly as in claim 2 wherein said metallic column
further comprises an alignment ring disposed axially between said
primary pole piece and said secondary pole piece.
4. A valve assembly as in claim 3 wherein said primary pole piece
and said secondary pole piece are each connected to said alignment
ring with a press fit connection.
5. A valve assembly as in claim 3 wherein said primary pole piece
and said secondary pole piece are each made of a magnetic metal and
wherein said alignment ring is made of a non-magnetic metal.
6. A valve assembly as in claim 3 wherein said primary pole piece
and said secondary pole piece are each part of the magnetic circuit
of said solenoid subassembly.
7. A valve assembly as in claim 1 wherein said solenoid housing
base includes a solenoid housing base aperture extending
therethrough and wherein said metallic column is press fit within
said solenoid housing base aperture.
8. A valve assembly as in claim 1, wherein an armature is disposed
within said metallic column, said armature being axially moveable
in a first direction along said valve axis when said coil is
energized with an electric current, said armature being axially
moveable in a second direction along said valve axis that is
opposite said first direction when said coil is not energized with
an electric current, and wherein said armature affects the position
of said valve member.
9. A valve assembly having a hydraulic subassembly with a valve
member displaceable along a valve axis for controlling flow of
fluid from a fluid source to a working device, said valve assembly
also having a solenoid subassembly for selectively displacing said
valve member, said solenoid subassembly comprising: a metallic
solenoid housing having an open end distal from said hydraulic
subassembly and a solenoid housing base adjacent to and connected
with said hydraulic subassembly; a solenoid coil assembly disposed
within said solenoid housing, said solenoid coil assembly having a
coil wound around a plastic spool defining a spool bore extending
through said spool; a metallic solenoid housing cover closing off
said open end of said solenoid housing and attached to said
solenoid housing with a crimp connection that creates a compressive
crimp force acting along said valve axis; and a metallic column
defined by a primary pole piece made of a magnetic metal, a
secondary pole piece made of a magnetic metal, and an alignment
ring made of a non-magnetic metal disposed between said primary
pole piece and said secondary pole piece.
10. A valve assembly as in claim 9 wherein said metallic column is
in compression between said solenoid housing base and said solenoid
housing cover.
11. A solenoid subassembly extending along a valve axis, said
solenoid subassembly comprising: a metallic solenoid housing having
an open end and a solenoid housing base opposing said open end; a
solenoid coil assembly disposed within said solenoid housing, said
solenoid coil assembly having a coil wound around a plastic spool
defining a spool bore extending through said spool; a metallic
solenoid housing cover closing off said open end of said solenoid
housing and attached to said solenoid housing with a crimp
connection that creates a compressive crimp force acting along said
valve axis; and a metallic column disposed within and passing
through said spool bore, said metallic column extending from said
solenoid housing base to said solenoid housing cover; wherein said
compressive crimp force is transferred through said metallic column
from said solenoid housing base to said solenoid housing cover to
isolate said compressive crimp force from plastic components.
12. A solenoid subassembly as in claim 11 wherein said metallic
column comprises: a primary pole piece of said solenoid
subassembly; and a secondary pole piece of said solenoid
subassembly.
13. A solenoid subassembly as in claim 12 wherein said metallic
column further comprises an alignment ring disposed axially between
said primary pole piece and said secondary pole piece.
14. A solenoid subassembly as in claim 13 wherein said primary pole
piece and said secondary pole piece are each connected to said
alignment ring with a press fit connection.
15. A solenoid subassembly as in claim 13 wherein said primary pole
piece and said secondary pole piece are each made of a magnetic
metal and wherein said alignment ring is made of a non-magnetic
metal.
16. A solenoid subassembly as in claim 13 wherein said primary pole
piece and said secondary pole piece are each part of the magnetic
circuit of said solenoid subassembly.
17. A solenoid subassembly as in claim 11 wherein said solenoid
housing base includes a solenoid housing base aperture extending
therethrough and wherein said metallic column is press fit within
said solenoid housing base aperture.
18. A solenoid subassembly as in claim 11, wherein an armature is
disposed within said metallic column, said armature being axially
moveable in a first direction along said valve axis when said coil
is energized with an electric current and said armature being
axially moveable in a second direction along said valve axis that
is opposite said first direction when said coil is not energized
with an electric current.
Description
TECHNICAL FIELD OF INVENTION
[0001] The present invention relates to a solenoid-actuated control
valve; more particularly to a solenoid-actuated control valve which
is resistant to pressure drift over time; and even more
particularly to a solenoid-actuated control valve which does not
place crimp assembly loads on plastic components within the
solenoid.
BACKGROUND OF INVENTION
[0002] Solenoid-actuated control valves, herein after referred to
as control valves, are well known to control the flow and/or
pressure of a fluid. In many applications, it may be desirable that
the flow and/or pressure output of the control valve be
proportional to an electric current supplied to a solenoid of the
control valve. In a common control valve arrangement, the electric
current supplied to the solenoid of the control valve affects the
position of a supply valve member and/or an exhaust valve member
relative to a supply valve seat and an exhaust valve seat
respectively. The position of the supply valve member relative to
the supply valve seat and/or the position of the exhaust valve
member relative to the exhaust valve seat affects the fluid flow
and/or pressure leaving the control valve. It is therefore
important that the position of the valve members relative to the
valve seats for a given electric current supplied to the solenoid
does not change during the life of the control valve because if the
position of the valve members relative to the valve seats is not as
is expected, the flow and/or pressure leaving the control valve may
not be the desired magnitude.
[0003] The solenoid of the control valve is typically enclosed in a
housing that is cylindrical and made of metal. An example of such a
control valve is shown in US Patent Application Publication No. US
2007/0138422 A1. During manufacturing of the control valve, at
least one end of the housing is open to allow components of the
solenoid to be placed within the housing. After all of the
components have been placed within the housings, a cover may be
placed over the open end, and the housing may be crimped or folded
over the cover to retain the cover to the housing. When the housing
is crimped to retain the cover, an axial load is placed on the
components within the housing and the axial load on the components
within the housing is maintained by the crimp connection. However,
this axial load from the crimp is known to be transmitted through
plastic components, such as the spool (also known as a bobbin or
coil former) around which the coil of the solenoid is wound. Over
time, this crimp load may cause the plastic components to creep
(i.e. change in shape and position), thereby changing the position
of the valve members relative to the valve seats for a given a
given electric current supplied to the solenoid. As a result, the
desired flow and/or pressure leaving the control valve may not be
the desired magnitude for a given electric current supplied to the
solenoid.
[0004] One way to address the effects of creep of the plastic
components and the changing of position of the valve members
relative to the valve seats over time is to use closed loop
feedback. In this arrangement, the actual flow and/or pressure
leaving the control valve is measured with a sensor. The sensor
sends a signal indicative of the flow and/or pressure to a
controller. If the signal indicates that the flow and/or pressure
is not the desired magnitude, the controller can alter the electric
current supplied to the solenoid until the desired flow and/or
pressure reaches the desired magnitude. In this way, the effects of
creep of plastic components can be overcome. However, using closed
loop feedback increases the cost and complexity of the system, for
example by the addition of sensors, wiring, and software.
[0005] What is needed is a control valve in which the flow and/or
pressure leaving the control valve does not change over time for a
given magnitude of electric current used to actuate the control
valve. What is also needed is a control valve which is not affected
by creeping of plastic components of the solenoid over time.
SUMMARY OF THE INVENTION
[0006] Briefly described, a valve assembly includes a hydraulic
subassembly with a valve member displaceable along a valve axis for
controlling at least one of flow and pressure of fluid from a fluid
source to a working device. The valve assembly also includes a
solenoid subassembly for selectively displacing the valve member.
The solenoid subassembly includes a metallic solenoid housing
having an open end distal from the hydraulic subassembly and a
solenoid housing base adjacent to and connected with the hydraulic
subassembly. The solenoid subassembly also includes a solenoid coil
assembly disposed within the solenoid housing, the solenoid coil
assembly having a coil wound around a plastic spool defining a
spool bore extending through the spool. The solenoid subassembly
also includes a solenoid housing cover closing off the open end of
the solenoid housing and attached to the solenoid housing with a
crimp connection that creates a compressive crimp force acting
along the valve axis. The solenoid subassembly also includes a
metallic column disposed within and passing through the spool bore,
the metallic column extending from the solenoid housing base to the
solenoid housing cover. The compressive crimp forces are
transferred through the metallic column from the solenoid housing
base to the solenoid housing cover to isolate the compressive crimp
forces from plastic components.
BRIEF DESCRIPTION OF DRAWINGS
[0007] This invention will be further described with reference to
the accompanying drawings in which:
[0008] FIG. 1 is a cross section of a valve assembly in accordance
with the invention shown in a position which allows full pressure
and/or flow from a fluid source to a working device;
[0009] FIG. 2 is an exploded isometric view of the valve assembly
of FIG. 1; and
[0010] FIG. 3 is the cross section of FIG. 1 now with the valve
assembly shown in a position which prevents fluid communication
from the fluid source to the working device.
DETAILED DESCRIPTION OF INVENTION
[0011] In accordance with a preferred embodiment of this invention
and referring to FIGS. 1 and 2, solenoid-actuated control valve 10
is shown, hereinafter referred to as valve assembly 10. Valve
assembly 10 includes hydraulic subassembly 12 in fluid
communication with fluid source 14 and working device 16. Working
device 16 may be, for example, a transmission clutch. Valve
assembly 10 also includes solenoid subassembly 18 which is
connected to hydraulic subassembly 12 and which controls the fluid
communication from fluid source 14 through hydraulic subassembly 12
to working device 16 based on an electric current which is variable
and which is supplied by electric current source 20. Electric
current source 20 may be, for example, an electronic
controller.
[0012] Hydraulic subassembly 12 includes hydraulic subassembly
housing 22 which may be made, for example, by injection molding a
plastic material. Hydraulic subassembly housing 22 extends along
valve axis A and includes attachment flange 24 at one axial end
which is used to attach hydraulic subassembly 12 to solenoid
subassembly 18. Hydraulic subassembly housing 22 also includes
inlet port 26 located in the axial end of hydraulic subassembly
housing 22 which is distal from attachment flange 24. Inlet port 26
is in constant fluid communication with fluid source 14. Hydraulic
subassembly housing 22 also includes working port 28 extending
radially outward from hydraulic subassembly housing 22. Working
port 28 is in constant fluid communication with working device 16
and is in variable fluid communication with inlet port 26 based on
input from solenoid subassembly 18. Hydraulic subassembly housing
22 also includes exhaust port 30 which is in variable fluid
communication with working port 28 based on input from solenoid
subassembly 18.
[0013] Hydraulic subassembly 12 also includes a supply valve member
shown as ball 34 which is located within inlet port 26 and which is
selectively seated and unseated with supply valve seat 36. Supply
valve seat 36 is annular, coaxial with valve axis A, and formed
between working port 28 and inlet port 26 to be small in diameter
than ball 34. In order to retain ball 34 within inlet port 26, ball
retainer 38 may be provided. Ball retainer 38 may be secured, for
example by press fit or welding, within an enlarged portion of
inlet port 26. A reduced diameter section of ball retainer 38 may
extend further into inlet port 26 to prevent ball 34 from escaping
inlet port 26 while still allowing for axial movement of ball 34
relative to supply valve seat 36 to allow for desired flow and/or
pressure from fluid source 14 to working device 16 when ball 34 is
not seated with supply valve seat 36.
[0014] Hydraulic subassembly 12 is also provided with poppet rod 40
in order transfer linear motion produced by solenoid subassembly 18
to ball 34 to selectively seat and unseat ball 34 with supply valve
seat 36. Poppet rod 40 is coaxial with valve axis A and sized to
extend through supply valve seat 36 such that a clearance is formed
radially outward of poppet rod 40 to allow fluid communication
radially between hydraulic subassembly housing 22 and poppet rod 40
from inlet port 26 to working port 28 when ball 34 is unseated with
supply valve seat 36. When ball 34 is to be unseated with supply
valve seat 36, poppet rod tip 42 contacts ball 34 and urges ball 34
away from supply valve seat 36.
[0015] Hydraulic subassembly 12 is also provided with exhaust seat
44 which is disposed within hydraulic subassembly housing 22
axially between working port 28 and exhaust port 30. Exhaust seat
44 is substantially disk-shaped and includes exhaust aperture 46
extending axially therethrough and coaxial with valve axis A.
Exhaust aperture 46 is sized to allow poppet rod 40 to pass
therethrough with sufficient radial clearance with poppet rod 40 to
allow fluid communication radially between exhaust aperture 46 and
poppet rod 40 from working port 28 to exhaust port 30. Exhaust
valve member 48 is fixed to poppet rod 40 and sized to be larger in
diameter than exhaust aperture 46. Poppet rod 40 is moveable based
on input from solenoid subassembly 18 to allow exhaust valve member
48 to be selectively seated and unseated with exhaust seat 44. In
this way, fluid communication from working port 28 to exhaust port
30 is substantially prevented when exhaust valve member 48 is
seated with exhaust seat 44. Conversely, fluid communication from
working port 28 to exhaust port 30 is permitted when exhaust valve
member 48 is not seated with exhaust seat 44. It should also be
noted that fluid communication from inlet port 26 to working port
28 is permitted when exhaust valve member 48 is seated with exhaust
seat 44 and that fluid communication from inlet port 26 to working
port 28 is substantially prevented for a portion of the travel of
poppet rod 40 in which exhaust valve member 48 is not seated with
exhaust seat 44.
[0016] Hydraulic subassembly 12 is also provided with exhaust seat
retainer 50 for retaining exhaust seat 44 within hydraulic
subassembly housing 22 and for guiding poppet rod 40. Exhaust seat
retainer 50 captures exhaust seat 44 axially between a shoulder
within hydraulic subassembly housing 22 and the axial end of
exhaust seat retainer 50 that is distal from solenoid subassembly
18. Exhaust seat retainer 50 is press fit or otherwise fastened
within hydraulic subassembly housing 22 to prevent relative
movement between exhaust seat retainer 50 and hydraulic subassembly
housing 22, thereby retaining exhaust seat 44 within hydraulic
subassembly housing 22. Exhaust seat retainer 50 is cup-shaped to
define exhaust chamber 52 radially outward of poppet rod 40/exhaust
valve member 48 which allows axial movement of exhaust valve member
48 within exhaust chamber 52. Exhaust seat retainer 50 includes
exhaust seat retainer aperture 54 extending axially therethrough
and coaxial with valve axis A. Exhaust seat retainer aperture 54 is
sized to be a clearance fit with poppet rod 40 such that poppet rod
40 is able to move axially substantially uninhibited while radial
movement of poppet rod 40 is substantially prevented.
[0017] Solenoid subassembly 18 includes solenoid housing 56 which
is made of a magnetic metal. Solenoid housing 56 includes a
substantially cylindrical section defining solenoid housing
sidewall 58. Solenoid housing 56 also includes solenoid housing
base 60 which extends radially inward from solenoid housing
sidewall 58 to partially close the end of solenoid housing 56 which
is proximal to hydraulic subassembly 12. Solenoid housing base 60
may be constructed as one piece with solenoid housing sidewall 58,
for example by a metal stamping process. Solenoid housing base 60
defines solenoid housing aperture 62 extending axially through
solenoid housing base 60 coaxial with valve axis A. Solenoid
housing 56 also includes attachment tabs 64 which are used to
retain hydraulic subassembly 12 to solenoid subassembly 18.
Attachment tabs 64 extend axially from solenoid housing sidewall 58
toward hydraulic subassembly 12. In FIG. 2, attachment tabs 64 are
shown as phantom lines as they appear after being crimped or folded
over attachment flange 24 of hydraulic subassembly housing 22 in
order to retain hydraulic subassembly 12 to solenoid subassembly
18. Attachment tabs 64 are also shown in FIG. 2 as solid lines as
they would appear prior to attachment tabs 64 being crimped over to
attach hydraulic subassembly 12 to solenoid subassembly 18.
[0018] Solenoid subassembly 18 also includes spool 66 which is made
of a material which does not conduct electricity, for example,
plastic. Spool 66 includes spool cylinder 68 which is coaxial with
valve axis A and spool bore 70 which extends axially through spool
cylinder 68 coaxial with valve axis A. Spool 66 also includes spool
rims 72, 74 which extend radially outward from the ends of spool
cylinder 68. Spool rim 72 extends radially outward from the end of
spool cylinder 68 which is proximal to solenoid housing base 60
while spool rim 74 extends radially outward from the end of spool
cylinder 68 which is distal from solenoid housing base 60.
Electrically conductive wire is wound around spool cylinder 68
between spool rims 72, 74 to form coil 76 which is connected to
terminals 78 which are connected to electric current source 20.
Spool 66 and coil 76 together define a solenoid coil assembly.
[0019] Solenoid subassembly 18 also includes primary pole piece 80
and secondary pole piece 82 which are each made of a magnetic
material. Primary pole piece 80 and secondary pole piece 82 are
sized to fit within spool bore 70 such that primary pole piece 80
and secondary pole piece 82 may be inserted within spool bore 70
without restriction. Primary pole piece 80 may be disposed proximal
to solenoid housing base 60 while secondary pole piece 82 may be
disposed distal from solenoid housing base 60. It should be noted
that primary pole piece 80 and secondary pole piece 82 are part of
the magnetic circuit of solenoid subassembly 80 which function to
control the magnetic flux distribution.
[0020] Primary pole piece 80 includes primary pole piece bore 84
which extends axially through primary pole piece 80 coaxial with
valve axis A. Primary pole piece bushing 86 is fixed within primary
pole piece bore 84, for example, by press fit. Primary pole piece
bushing 86 is made of a non-magnetic material, for example, bronze
or plastic and includes primary pole piece bushing bore 88 which
extends axially through primary pole piece bushing 86 coaxial with
valve axis A. Primary pole piece 80 is fixed to solenoid housing
base 60, for example, by press fit within solenoid housing aperture
62.
[0021] Secondary pole piece 82 includes secondary pole piece bore
90 which extends axially through secondary pole piece 82 coaxial
with valve axis A. Secondary pole piece bushing 92 is fixed within
secondary pole piece bore 90, for example, by press fit. Secondary
pole piece bushing 92 is made of a non-magnetic material, for
example, bronze or plastic and includes secondary pole piece
bushing bore 94 which extends axially through secondary pole piece
bushing 92 coaxial with valve axis A.
[0022] Primary pole piece 80 may be fixed to secondary pole piece
82 with alignment ring 96. Alignment ring 96 is cylindrical and
made of a non-magnetic material, for example, brass or stainless
steel. Alignment ring 96 is fixed to primary pole piece 80, for
example, by press fit with primary pole piece reduced diameter
section 98. Alignment ring 96 axially abuts primary pole piece
shoulder 100 which is defined by primary pole piece reduced
diameter section 98. Similarly, alignment ring 96 is fixed to
secondary pole piece 82, for example, by press fit with secondary
pole piece reduced diameter section 102. Alignment ring 96 axially
abuts secondary pole piece shoulder 104 which is defined by
secondary pole piece reduced diameter section 102. Alignment ring
96 is sized to fit within spool bore 70 such that alignment ring 96
may be inserted within spool bore 70 without restriction. Alignment
ring 96 is also sized to axially space primary pole piece 80 from
secondary pole piece 82.
[0023] Solenoid subassembly 18 also includes armature 106 which is
at least partly disposed within secondary pole piece bore 90 in a
clearance fit such that armature 106 is able to slide within
secondary pole piece bore 90 without restriction and such that
radial movement of armature 106 within secondary pole piece bore 90
is substantially prevented. Armature 106 is made of a magnetic
material and includes armature bore 108 which extends axially
through armature 106 and coaxial with valve axis A. Armature 106
may also be partially received within enlarged section 110 of
primary pole piece bore 84. Enlarged section 110 is sized to allow
unrestricted movement of armature 106 within enlarged section 110.
The axial position of armature 106 along valve axis A is variable
based on electric current supplied to coil 76 by electric current
source 20.
[0024] Solenoid subassembly 18 also includes connecting rod 112
which is received within primary pole piece bushing bore 88,
secondary pole piece bushing bore 94, and armature bore 108 coaxial
with valve axis A. Connecting rod 112 is sized to form a slip fit
with primary pole piece bushing bore 88 and secondary pole piece
bushing bore 94 such that connecting rod 112 is able to move
axially without restriction and such that radial movement of
connecting rod 112 is substantially prevented. Connecting rod 112
is fixed to armature 106, for example by press fit or staking such
that connecting rod 112 moves axially with armature 106 as a single
unit. Connecting rod 112 includes rod spring seat 114 which is
formed by a reduced diameter end of connecting rod 112 that is
proximal to hydraulic subassembly 12. The end of connecting rod 112
that is proximal to hydraulic subassembly 12 is fixed to poppet rod
40. In this way, axial movement of armature 106/connecting rod 112
is translated to axial movement of poppet rod 40.
[0025] Return spring 116 radially surrounds a portion of poppet rod
40 and a portion of connecting rod 112. Return spring 116 is
disposed axially between exhaust seat retainer 50 and rod spring
seat 114 to bias poppet rod 40/connecting rod 112/armature 106 away
from hydraulic subassembly 12.
[0026] Solenoid subassembly 18 also includes solenoid housing cover
118 made of a magnetic metal for closing the end of solenoid
housing 56 which is distal from solenoid housing base 60. Solenoid
housing cover 118 includes alignment tabs 120 that extend radially
outward from solenoid housing cover 118. Alignment tabs 120 fit
within solenoid housing notches 122 formed in solenoid housing
sidewall 58 of solenoid housing 56 (only one solenoid housing notch
122 is visible in FIG. 2). Attachment tabs 124 extend axially away
from solenoid housing sidewall 58 to define solenoid housing
notches 122. In FIG. 1, attachment tab 124 is shown as a solid line
as it appears after assembly and being crimped (i.e. folded over)
to retain solenoid housing cover 118. Also in FIG. 1, attachment
tab 124 is shown as a phantom line as it would appear prior to the
folding or crimping operation. In FIG. 2, attachment tabs 124 are
shown only as they would appear prior to the folding or crimping
operation. Solenoid housing cover 118 includes recessed section 126
which may be formed, for example, by a stamping operation. Recessed
section 126 is formed with a diameter to receive a portion of
secondary pole piece 82 therewithin.
[0027] After attachment tabs 124 have been crimped to retain
solenoid housing cover 118, an compressive crimp load exists on
solenoid housing cover 118 along valve axis A. This crimp load is
counteracted at the outer edge of solenoid housing cover 118 by
solenoid housing sidewall 58. This crimp load is also counteracted
radially inward of the outer edge of solenoid housing cover 118 by
a metallic column which may be formed by the combination of primary
pole piece 80, alignment ring 96, and secondary pole piece 82. It
should be noted that if primary pole piece 80 is attached to
solenoid housing base 60 by a press fit within solenoid housing
aperture 62, the force required to move primary pole piece 80
relative to solenoid housing base 60 must be greater than the axial
force acting on primary pole piece 80/alignment ring 96/secondary
pole piece 82 as a result of attachment tabs 124 being crimped over
to retain solenoid housing cover 118. In this way, the crimp load
is isolated from plastic components and consequently the crimp load
is not supported by any plastic components which could creep over
time due to the crimp load. Creep of plastic parts over time due to
the crimp load may cause a change in the position over time of
poppet rod 40/connecting rod 112/armature 106 for a given electric
current applied to coil 76 compared to the position of poppet rod
40/connecting rod 112/armature 106 at the same given electric
current applied to coil 76 when valve assembly 10 is first
manufactured.
[0028] When electric current source 20 applies an electric current
of sufficient magnitude to coil 76, a magnetic field is generated
through a magnetic circuit which includes primary pole piece 80,
armature 106, secondary pole piece 82, solenoid housing cover 118,
and solenoid housing 56. The magnetic field creates an attractive
force between armature 106 and primary pole piece 80, thereby
causing armature 106 to move toward primary pole piece 80 and
compressing return spring 116. The magnitude that armature 106
moves may be proportional to the magnitude of electric current
applied to coil 76 in order to precisely control the axial position
of armature 106. When the electric current applied to coil 76 is
decreased or stopped, return spring 116 urges armature 106 in the
upward direction as viewed in FIG. 1.
[0029] In operation and referring to FIG. 1, valve assembly 10 is
shown in an operational state in which maximum flow and/or pressure
is permitted to be supplied from fluid source 14 to working device
16. This is accomplished by electric current source 20 applying a
current to coil 76 sufficient to axially move armature 106/poppet
rod 40/connecting rod 112 until exhaust valve member 48 contacts
exhaust seat 44. When this occurs, return spring 116 is compressed
and ball 34 is unseated with supply valve seat 36 by poppet rod tip
42. Ball 34 may be moved further away from supply valve seat 36 by
fluid from fluid source 14 until ball 34 contacts ball retainer 38.
In this way, the maximum amount of flow and/or pressure of the
fluid from fluid source 14 is applied to working device 16. Arrows
S are used to illustrate the pressure and/or flow fluid supplied by
fluid source 14.
[0030] In operation an now referring to FIG. 3 valve assembly 10 is
shown in an operational state in which flow and pressure is
prevented from being supplied from fluid source 14 to working
device 16. This is accomplished by stopping electric current source
20 from applying a current to coil 76 or decreasing the current to
a magnitude such that return spring 116 axially urges armature
106/poppet rod 40/connecting rod 112 to a position that prevents
poppet rod tip 42 from interfering with ball 34 from seating with
supply valve seat 36. When this occurs, exhaust valve member 48 is
lifted from exhaust seat 44 to allow fluid to exit valve assembly
10 through exhaust port 30. This allows ball 34 to seat against
supply valve seat 36 by the flow and/or pressure of fluid from
fluid source 14, thereby preventing fluid communication from fluid
source 14 to working device 16. Arrows E are used to illustrate the
exhaust of fluid from working device 16 to exhaust port 30.
[0031] While not shown, it should now be understood that electric
current source 20 may apply a current to coil 76 sufficient to
axially move armature 106/poppet rod 40/connecting rod 112 to
positions that are intermediate of the positions shown in FIGS. 1
and 3. This allows some flow and/or pressure of fluid from fluid
source 14 to escape to exhaust port 30 in order to decrease the
flow and/or pressure of fluid supplied to working device 16,
thereby achieving a desired flow and/or pressure of fluid to
working device 16.
[0032] Valve assembly 10 has been illustrated as preventing fluid
communication from fluid source 14 to working device 16 when coil
76 is not supplied with an electric current and has also been
illustrated as preventing fluid communication from working device
16 to exhaust port 30 when a maximum electric current is applied to
coil 76 which is commonly referred to as a "normally low" valve
because the default operation (i.e. no electric current) of valve
assembly 10 results in low flow and/or pressure to working device.
It should now be understood that valve assembly 10 may also be
configured to be a "normally high" valve by reversing the positions
of primary pole piece 80 and secondary pole piece 82 and
repositioning return spring 116 to urge poppet rod 40/armature
106/connecting rod 112 toward hydraulic subassembly 12. This
arrangement would make the default operation (i.e. no electric
current) to allow maximum flow and/or pressure of fluid to working
device 16 from fluid source 14.
[0033] While solenoid subassembly 18 has been shown in the context
of actuating a valve, it should now be understood that the use of
solenoid subassembly 18 need not be limited to actuating valves,
but may be used in other applications where linear motion generated
by a solenoid is commonly used. It this way, the magnitude of
linear motion produced by solenoid assembly 18 may be precisely
controlled over time for a given electric current since creeping of
plastic components within solenoid assembly 18 due to crimp forces
is eliminated.
[0034] While this invention has been described in terms of
preferred embodiments thereof, it is not intended to be so limited,
but rather only to the extent set forth in the claims that
follow.
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